Presently available imaging diagnostic apparatuses for capturing diagnostic images of patients include CT scanners, MRI (Magnetic Resonance Imaging) apparatuses, PET (Positron Emission Tomography) apparatuses, ultrasonic diagnostic apparatuses, CT angiography apparatuses, MRA (MR angiography) apparatuses and the like. When the abovementioned imaging diagnostic apparatuses are used, a liquid such as a contrast medium and physiological saline may be injected into a patient. Chemical liquid injectors for automatically performing the injection have been put into practical use.
Such a chemical liquid injector has a liquid injection mechanism formed of a driving motor, a slider mechanism and the like, for example. A liquid syringe is removably mounted on the injector. The liquid syringe typically comprises a cylinder member and a piston member slidably inserted in the cylinder member. There are a pre-filled type and a refill type in the liquid syringe.
The liquid syringe of the pre-filled type includes a cylinder member filled with a liquid and is wholly sealed by a packing material for shipment. The liquid syringe of the refill type includes a cylinder member which can be filled with a desired liquid by a user. For simplicity, the following description will be made assuming that the liquid syringe of the pre-filled type is used.
For injecting the liquid into a patient from the liquid syringe of the abovementioned type, an operator prepares for a liquid syringe containing an appropriate liquid and takes out the liquid syringe from the packing material. The operator connects the liquid syringe to a patient through an extension tube and mounts the liquid syringe on a liquid injection mechanism of a chemical liquid injector. In response to a predetermined operation, the chemical liquid injector moves the piston member relative to the cylinder member with the liquid injection mechanism to inject the liquid into the patient from the liquid syringe.
The operator determines the rate at which the liquid is injected and the total quantity of the liquid to be injected in view of the type of the liquid and the like, and enters data representing the rate and total quantity into the chemical liquid injector. The chemical liquid injector injects the liquid into the patient based on the entered data. For example, when a contrast medium is injected as the liquid, the image contrast of the patient is changed to allow the imaging diagnostic apparatus to capture a favorable diagnostic image of the patient.
Some chemical liquid injectors can inject physiological saline as well as the contrast medium into the patient. In such a chemical liquid injector, the operator enters as desired an instruction to inject the physiological saline following the completion of the injection of the contrast medium, together with data representing the injection rate and total quantity of the physiological saline, into the chemical liquid injector. The chemical liquid injector first injects the contrast medium into the patient based on the entered data and then automatically injects the physiological saline. The subsequently injected physiological saline can push the previously injected contrast medium to reduce the consumption of the contrast medium and also can reduce artifacts in the captured image.
Some chemical liquid injection system currently proposed have a data storing means such as an RFID chip and a bar code put on a liquid syringe such that the data stored thereon is read out by a chemical liquid injector (see, for example, Patent Documents 1 and 2 below).
Patent Document 1: U.S. Pat. No. 5,840,026
Patent Document 2: Japanese Patent Laid-Open No. 2004-298550